Pilot-Scale Demonstration of Biosurfactant-enhanced In-situ Bioremediation of a Contaminated Site in Newfoundland and Labrador
Soil and groundwater contamination caused by oil and chemical spills are among the most extensive and environmentally damaging pollution problems and are recognized as potential threats to human and ecosystem health. It is generally thought that spills are more damaging in cold regions such as Newfoundland and Labrador (NL), where ecosystem recovery is slower than those in warmer climates. The contamination not only poses an adverse impact on human and environment health, but also leads to an economic loss in NL. In 2007-08, 482 of 2269 federal contaminated sites were determined in Atlantic Canada, with 331 in NL, resulting in a large number of remediation projects. The Goose Bay Remediation Project (GBRP) was one of the major projects with an investment over $258 million.
Industries have attempted to solve individual problems and/or processes related to site remediation practices in Goose Bay in past years and they are expecting effective and cost-efficient in-situ remediation technologies which can be directly applicable to NL. In-situ bioremediation has been proven as a promising technology through both experimental studies and field applications for cleaning up petroleum hydrocarbons (PHCs) from subsurface due to its low cost and the lack of toxic by-products which are commonly associated with other treatment types. However, there are challenges to apply bioremediation to NL sites, especially in an in-situ way. In NL, a number of contaminated sites are PHCs and heavy metal co-contaminated sites. The metals can inhibit the natural microbiota and hence impede the rate of PHC degradation. Moreover, bioremediation is currently still a site-dependent action, with many applications relying on demonstrating efficacy at sites of a certain region. Natural conditions in NL are different from other parts of the world (e.g., cold weather and relatively low incidence of sunlight, resulting in a decrease in both abiotic transformation and biotic degradation of contaminants). Therefore, existing in-situ bioremediation techniques are not directly suitable in the NL context.
The project aimed at the design, implementation and assessment of a pilot-scale demonstration of biosurfactant-enhanced in-situ bioremediation at a PHC and heavy metal co-contaminated site in NL. The large-scale laboratory setup could combine the advantages of controlled experimentation conditions with the scale that can facilitate either direct application of the results, or precise extrapolation. Through a number of experimental studies, the study expected to generate environmental friendly and economical/technical feasible solutions for helping solve the challenging site contamination problem in this region; and to be directly applicable to the NL context. It entails the following research tasks:
(1) To determine a target NL contaminated site and conduct site characterization;
(2) To design subsurface soil profile and generate the conceptual model of the site subsurface based on boreholes drilling reports, the analysis of soil and water samples from surrounding boreholes, and the mathematical modeling;
(3) To realize the conceptual model and scale-down the real site conditions through the design and setup of a pilot-scale experimental system. Soil (sand, till, clay) will be selected, analyzed and loaded to the pilot-scale vessel;
(4) To produce biosurfactants in lab and conduct the pilot-scale biosurfactant-enhanced bioremediation experiments for cleaning up real-site contaminants under typical subsurface conditions within the NL site; and
(5) To examine the performance of biosurfactants and the associated bioremediation technologies during the pilot-scale test.
The research and developed technologies will help to (a) obtain improved and applicable technologies for site remediation in NL; (b) reduce costs at the consulting, planning, design and operation stages associated with the site remediation practices; (c) develop multidisciplinary expertise in remediation engineering, environmental chemistry and biology, and experimental design for personnel training; and (d) demonstrate technical transfer and facilitate convenient current state and future fields of application to the industries.
The full report can be found here.